Meet my new boy, D'Artagnan. He came home with us with his fins looking like this. We've had him for 2 and a half days now. I am almost positive that it is fin rot, due to the jagged appearance at the ends. My husband thinks it is his natural coloration. What do y'all think?

What has me doubting myself is that I have seen virtually no improvement since we got him. He's been getting the full fin rot spa treatment. Half gallon QT tank floated in my heated 20 gallon, daily 100% WC, IAL, AQ salt at 1 tsp/gallon, StressGuard, VitaChem, he got bloodworms last night for good protein. I know it's only been 2 1/2 days, but it seems he should be showing some signs of improvement.

Keep a close eye on the fish, if the fins start to rip even more its fin rot. But if not its probably just coloration.
If you want, try putting a mirror in front of the tank, cos a sick betta wont flare, but if he does you shouldnt be to concerned :3
And as long as hes eating and not just staying on the bottom of the tank, he should be fine.

As far as his behavior goes, he's acting great. He really wants to get out and explore. But from my experience with fin rot, unless it's a symptom of a larger problem, behavior usually seems to stay normal.

At least, an advantage of keeping him in the QT is that he won't be overcome by shell shock when he goes from living in a tiny cup his whole life, to a heavily planted 20L inhabited by maniacal kuhli loaches.

I think you just need to give it some more time. The best way to treat fin rot is with warm, clean water and good nutrition. Right now, you're providing all of that, but he may just need a little more time.

Are you QTing him in the half-gal because of the fin rot, or because you normally QT new fish?

Because of the fin rot- I don't want to add salt to the tank that he will be going in because there are loaches in there. Normally I wouldn't have QT'd him since he didn't come from a community tank. I know QT'ing new fish is considered wise, but I don't usually.

Yes, it looks like fin rot to me. But it doesn't appear to be extensive. Personally, I would stop the aquarium salt. I worry about the stress that the aquarium salt places on the kidneys. Yes, there are times when it's useful. But I prefer not to expose them to salt, if I feel that all that's really needed is warm, clean water, good nutrition and some time. But again, that's me.

I also worry about the ammonia levels in a small 0.5 gal tank. I know he'll freak out in the big tank, because it's sooooo big. But the larger tank will likely have a more stable water chemistry, with lower levels of ammonia and toxins. And that's what I think his fins need right now.

(That said, the stress of moving to the large tank may cause him to start tailbiting. So watch for that! If it's not one thing, it's usually another. LOL)

Sorry for not responding, guys. Had a big weekend. Just wanted to say thanks for the confirmation that it was fin rot.

I did end up putting him in the 20. He took to it great, no stress at all- my new little guy is a real champ. So, it's watch and wait. I still don't see much improvement, but it is not progressing and that's a good sign in itself.